Firing pin with plastic sleeve for firearms



July 15, 1958 R. L. HILLBERG 2,842,885

FIRING PIN WITH'PLASTIC SLEEVE FOR FIREARMS Filed July 27, 1954 26 as r7 ,5 5 52 .5 5 Inventor ROBERT L. HILLBERG by M1 QMM Q Attorneys UnitedStates Patent FIRING PIN WITH PLASTIC SLEEVE FOR FIREARMS Robert L.Hillberg, West Cheshire, Conrn, assignor to The High StandardManufacturing Corporation, Hamden,Conn., a corporation of ConnecticutApplication July 27, 1954, Serial No. 446,053

1 Claim. (Cl. 42-69) This invention relates to firing pins for firearms,and more particularly to a firing pin assembly cushioned against shock,whereby to minimize breakage and lengthen the life of the pin. e

, It is common practice, particularly in the automatic pistol field, tomount the firing pin in a housing in which it is freely reciprocablelongitudinally, within limits, such housing in the case of an automaticpistol being the slide, of course. In other types of firearms thishousing will be a bolt or breech block, as the case may be, depending onthe particular type of gun. The firing pin itself is generally ofunitary construction and comprises a body portion and a reduced diameterportion, the forward end of which is adapted to' strike the primer of acartridge to fire the round. A stop is provided within the pin housingto contact the pin shoulder, formed at the, junction of its body portionand reduced diameter portion, to prevent excessive forward motion .ofthe pin during firing. The body portion of the pin is usual- 1y notchedor partially cut away to accommodate a detent orretaining pin adapted tohold the firing pin within the housing and limit its maximum rearwardlongitudinal movement.

When the pistol is fired, the hammer will strike the rear end of thebody portion of the pin, and will drive the pin forward until itsshoulder strikes the pin stop. The shock of this contact, which isespecially acute if the trigger is pulled when there is no cartridge inthe gun chamber,will in many cases cause the pin to break after repeateduse. This may occur either at the cut-away portion of the pinor alongits reduced section. It has been proposed in the pastto cushion thisshock by interposing a spring between the pin shoulder and the stop, butdue to space limitationswithin the slide or other pin housing as thecase may be, it has been found impracticablein most cases to .placetherein a spring of sutficient strength to be effective or which isitself sufiiciently free froin liability'to breakage.

It is accordingly an object ofthis invention to provide a firing pinembodying cushioning means for effectively reducing the shock whenthelpin shoulder is driven against the pin stop, thereby toincrease thelife of the pin. It is a furthenobject to provide such cushioning meanswhich is also effective for supporting the reduced diameter portion ofthe firing pin, while permitting free, sliding movement of the pin inits housing.

It has been found that the foregoing objects may be attained bylengthening the reduced diameter portion of the pin, and fitting asleeve of nylon, Saran, or other tough plastic over the reduced diameterportion. Such a sleeve may be used alone or in conjunction with acooperating metal sleeve or sleeves designed to take the wear off theplastic sleeve directly. Now, when the pistolis fired, the plasticsleeve will be effectively interposed between the pin shoulder and thestop, and will take up sufficient of the shock to greatly reducebreakage. In fact, it has been found in a series of tests, that by useof the plastic sleeve, breakage of the pin lCC is materially reduced andit is believed in fact that the life of the pin is thus substantiallydoubled.

In order that those skilled in the art may be more fully advised of thenature of the invention and of a means for carrying it out, it will bemore fully described in connection with the accompanying drawings inwhich:

Fig. l is a cross-sectional view in elevation of a portion of anautomatic pistol slide incorporating the new firing pin assembly, thepin being shown in withdrawn position, said assembly being the presentlypreferred embodiment of the invention in which a plastic sleeve isinterposed between two metal sleeves on the reduced portion of .thefiring pin;

Fig. 2 is a cross-sectional view similar to that of Fig. 1 showing thefiring pin in firing position to which .it has been advanced by thehammer;

Fig. 3 is a cross-sectional view of the pistol slide and firing pin asit would appear when viewed along line 3-3 of Fig. 1;

Fig. 4 is a plan view on agreatly enlarged scale of the firing pinmember alone;

Fig. 5 is a cross-sectional view of the inner or rear metal sleeve ofthe assembly shown in Figs. 1 and 2;

Fig. 6 is a cross-sectional view taken along line 66 of Fig. 5;

Fig. 7 is a cross-sectional view of the intermediate or plastic sleeveshown in Figs. 1 and 2;

.Fig. 8 is a cross-sectional view of the outer or front metal sleeve inthe aforesaid assembly; and

Figs. 9, l0, and 11 are cross-sectional views of alternative forms ofthe new firing pin assembly, the pins in these views being rotated 90about their longitudinal axis from the position shown in Fig. 4.

Referring to the embodiment of the invention shown in Figs. 1 through 8,the firing pin assembly, indicated generally at 20, is carried in thebreech block portion 21 formed integrally in the slide 22 of anautomatic pistol. Assembly 20 comprises a shouldered pin 23 having amain body portion 24 and a projecting portion of reduced diameterforming a nose 25 upon which cylindrical sleeves 26, 27 and 28 arecarried. The firing pin assembly 20 is disposed in a bore 29, withinwhich the forward end of nose 25' of pin 23 makes a sliding fit, and acounterbore 38 within which the body 24 of the pin likewise makes asliding fit. In order to retain the firing pin assembly within thebreech block 21, the pin is partially cut away in its main body 24 toprovide an elongated channel or notch 31, and a detent or retaining pin32 carried in a vertical hole 33 of slide 22 intersects counterbore 30adjacent notch 31 so that longitudinal movement of the pin is limited byengagement of the shoulders of the notch against the retaining pin. Thisretaining pin serves only to prevent the firing pinassembly fromfallingout of the rear of the-breech block 21 and is not the means by which theforward movement of the pin is normally intended to be limited in firingthe gun.

As shown in Figs. 1 and 2, a rearwardly facing beveled stop 34 is formedin breech block 21 at the junction of bore 29 and counterbore 30. Thefiring pin 23, in turn, has a shoulder 35 which provides a forwardlyfacing stop at the junction of its nose portion 25 and main body portion24. The aforesaid sleeves 26, 27 and 28 are disposed on the nose portion25 of pin 23 intermediate the 3 Sleeve 28 is also made of steel and hasa beveled forward face 38 adapted to engage stop 34 of the breech block21 when the firing pin is driven forwardly by hammer 41 of. the pistol,as well as a squared rear face 39. Sandwiched betweenthese steel sleevesis a sleeve 27 of nylon, Saran or other similar tough resilient plastic'or plastic-like material. Both the fore and aft faces 40, 41,respectively, of this sleeve are squared so as to abut firmly againsttheir respectively mating surfaces 39, 37 of sleeves 28 and 26; Thefiring pin 23 is freely slidable between a retracted or retired positionin thebreech block 21 as shown in Fig. 1, and a firing position, as seenin Fig. 2. In the retired position of the pin, the tip of the noseportion 25 is behind the forward face 42 of the breech block 21 whilethe rear end 43 of the pin projects outwardly beyond the rear face 44 ofthe breech block. In the firing position, the hammer 41 drives the pinforward to cause its nose to project beyond the face 42 and strike theprimer (not shown) of a shell chambered in the gun.

When the pistol is fired, the hammer strikes the rear end 43 of thefiring pin 23 and forces it forward until the forward face 41 of sleeve28 contacts the stop 34 in breech block 21. Since a very substantialforce must be applied to the firing pin in order to insure againstmisfires, there is considerable shock incurred when the forward motionis suddenly terminated. This shock often causes breakage in theconventional firing pins after the gun has been used for some time. Whenthe composite firing pin of the type just described is used, however,the plastic sleeve takes up a substantial portion of this shock anddampens vibration, thus greatly minimizing the occurrence of breakage.

Other modifications of the novel firing pin assembly are illustrated inFigs. 9 through 11. These modifications omit one or more of the metalsleeves used in the preferred embodiment of the invention describedhereinabove. In the construction shown in Fig. 9, for example, theforward sleeve 28 has been dispensed with and the short plastic sleeve27 replaced by a longer sleeve 46 having a beveled front face 47 adaptedto engage stop 34. While this form of assembly is lms expensive than the3-sleeve assembly previously disclosed, continuous pounding of the frontface 47 against the beveled stop 34 may tend to deform the plasticmaterial slightly and cause sticking of the firing pin in the breechblock. If this occurs, however, sleeve 46 is easily and economicallyreplaceable.

In the embodiment illustrated in Fig. 10, the inner and outer metalsleeves 26 and 28 have been eliminated and have been replaced by asingle plastic sleeve 48. In order to eliminate the inner metal sleeve26, however, it is necessary to machine the firing pin 23 to eliminatethe small fillet 49 by which the nose 25 is faired into body 24 in theconstruction shown in Fig. 4. Sucha fillet has a tendency to ride underand expand the material of the sleeve, rapidly disrupting the sleevecausing the firing pin to stick in the breech block. It has been foundthat the cost ofmachining an accurately squared face on this shouldermay approximate the cost of a separate metal 4 sleeve such as the sleeve26 whose squared face 37 is easily formed by a cut-off operation so thatthis particu-- lar embodiment of the invention is somewhat lesspreferable than that previously described.

There is also shown in Fig. 11 a further combination in which a plasticsleeve 50 and a single metal sleeve 28- are employed. While this form ofthe invention eliminates the deformation of the outer end of the plasticsleeve arising from impact against stop 34, it is subject to the samedifficulty as that shown in the pin of Fig. 10 with regard to thenecessity for providing for a squared shoulder 35 on the firing pin.Because of the comparative smallness of a firing pin of this type,especially in .22" calibre guns where the pin may conventionally be onlyfrom an inch and one-quarter to an inch and three-quarters long and havea maximum body diameter of less than one-eighth of an inch in itsreduced nose portion, it becomes somewhat diflicult to machine theshoulder withoutleaving the small radius or fillet 49 at the junction ofthe nose and body portions. However, it may be that an improved methodof fabrication will be discovered whereby such fillet can easily beeliminated, in which case the constructions shown in Figs. 10 and 11 maythen be preferred since they will then be less expensive to manufacturethan the type shown in Figsj 1 and 2.

What is claimed is:

In a firearm, the combination comprising a breech block having a passagetherein, a firing pin slidably mounted in said passage for limitedlongitudinal movement therein, said firing pin having a body portionfitting a first section of said passage anda reduced diameter noseportion extending from said body portion and fitting within a secondsection of said passage of correspondingly reduced diameter, a stopshoulder being formed between said sections of said passage and anoppositely facing shoulder being formed on said firing pin by thejuncture of said body and nose portions, said shoulders being positionedrelative to eachother to limit the forward travel of said firing pin;and a sleeve of tough, resilient, plastic material having propertiessimilar to nylon, said sleeve fitting closely on said nose portion alonga part of its extent adjacent the firing pin shoulder to provide acushion between said shoulders, the outside diameter of said sleevebeing essentially the same as that of said body portion so that saidsleeve swells into integral engagement with the wall of the firstsection of said passage when it is compressed between said shouldersupon actuation of the firing mechanism of said firearm.

References Cited in the file of this patent UNITED STATES PATENTS882,594 Talbot, Mar. 24, 1908 1,090,351 Swebilius et al Mar. 17, 19142,346,692 Lucht Apr. 18, 1944 2,418,946 Loomis Apr. 15, 1947 2,724,303Holcomb Nov. 22, 1955 FOREIGN PATENTS 325,090 Great Britain Feb. 13,1930

